//  Copyright (c) 2017-2018 Uber Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package tree

import (
	"github.com/uber/aresdb/query/sql/util"
)

// JoinOn is natural join
type JoinOn struct {
	// IJoinCriteria is interface
	IJoinCriteria
	Expr IExpression
}

// NewJoinOn creates JoinOn
func NewJoinOn(expr IExpression) *JoinOn {
	util.RequireNonNull(expr, "expression is null")
	return &JoinOn{
		Expr: expr,
	}
}

// GetNodes returns empty
func (j *JoinOn) GetNodes() []INode {
	return []INode{
		j.Expr,
	}
}
